Mint (Mentha spicata L.) is an important medicinal herb that is cultivated in different places of the world. In order to investigate effects of salinity stress on morphological characteristics of (Mentha spicata L.) a greenhouse experiment was conducted based on complete randomized in hydroponic condition with 5 treatments and 4 replications at Ferdowsi University of Mashhad in 2013. The salinity levels were (0, 30, 60, 90 and 120 mML -1 ) sodium chloride. The results showed that salinity stress had significant effects on plant height, branch number, node number, fourth internode length, spike length, leaf area and leaf, stem and root fresh and dry weight. The highest plant height, branch number, leaf area and leaf dry weight were observed in control. The lowest leaf area and leaf dry weight were obtained in salinity level of 120 mML -1 , and lowest plant height and branch number were observed in salinity level of 90 mML -1 and 120 mML -1 . Salinity had no significant effect on the number of stem and stem diameter. According to the results, it appears that mint (Mentha spicata L.) is sensitive to salinity stress and it can't tolerate salinity levels more than 30 mML -1 sodium chloride

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